Schiit Hel looks pretty awesome. Also more future proof than the fulla I think with the gain switch, you’d be able to use it with harder to drive headphones in the future. This is on Schiit’s website:
So why would I spend $90 more on this than Fulla 3?
Because you want more power or flexibility. Hel delivers 4x the power of Fulla 3, it has a gain switch for harder-to-drive or more sensitive headphones, it has a switchable analog input, and it has front-panel adjustable microphone gain and a stereo mic input. If any of those features are important, it might be worth $90 more than Fulla 3 for your needs.
Might get one myself.